A cup of brewed black tea has about 47 mg of caffeine per 8 oz (237 ml), about 71 mg per 12 oz and about 95 mg in a 16 oz mug, roughly half the caffeine of the same size of coffee. USDA lists 20 mg of caffeine per 100 g of brewed black tea (USDA FoodData Central), and the FDA lists 71 mg for 12 ounces (FDA). Real cups vary: lab tests of white, green and black teas found 14 to 61 mg per 6 or 8 oz serving, and steep time changed the result (Chin et al., 2008). This guide covers caffeine per cup, black tea vs coffee and green tea, and how to brew for more or less.
It is educational, not medical advice.
Key Takeaways
- Per 8 oz: about 47 mg of caffeine in brewed black tea (USDA FoodData Central).
- Per 12 oz: about 71 mg (FDA).
- Vs coffee: brewed coffee has about 95 mg per 8 oz (USDA FoodData Central).
- Steep time matters: in lab tests, steep time changed caffeine, and teas ranged from 14 to 61 mg per serving (Chin et al., 2008).
- Decaf and herbal: decaf teas had under 12 mg per serving and herbal teas had none detected (Chin et al., 2008).
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Caffeine in Black Tea by Cup Size
| Serving | Caffeine | Source |
|---|---|---|
| 6 oz cup | about 36 mg | USDA FoodData Central |
| 8 oz cup | about 47 mg | USDA FoodData Central |
| 12 oz cup | about 71 mg | FDA |
| 16 oz cup | about 95 mg | USDA FoodData Central |
The 6, 8 and 16 oz figures are calculated from the USDA value of 20 mg per 100 g of brewed black tea, with 6 fl oz weighing 178 g and 8 fl oz 237 g (USDA FoodData Central). The 12 oz figure is the FDA typical amount (FDA). Tea bags, loose leaf, water temperature and steeping time all change the real number.
Black Tea vs Coffee
Cup for cup, black tea has about half the caffeine of coffee: about 47 mg against about 95 mg per 8 oz (USDA FoodData Central; USDA FoodData Central). Lab tests reached the same conclusion: most brewed teas contained less caffeine per serving than brewed coffee (Chin et al., 2008). Our guide to tea vs coffee compares the two in more depth, including what large reviews found for each.
Black Tea vs Green Tea Caffeine
On average, black tea has more: about 47 mg per 8 oz against about 28 mg for green tea (USDA FoodData Central; USDA FoodData Central). But individual teas overlap a lot. In lab tests of 20 tea products, white, green and black teas all fell in the 14 to 61 mg range, with no clear trend by type of tea (Chin et al., 2008). Black and green tea come from the same plant; black tea leaves are oxidized during processing, green tea leaves are not (Graham, 1992). Our guide to green tea vs black tea covers the other differences.
Chai is black tea brewed with spices; see how much caffeine is in chai tea for chai and chai lattes.
Oolong is the partly oxidized tea between black and green; see how much caffeine is in oolong tea for its cup sizes.
If you want a paler tea, caffeine in white tea shows why white tea is not always lower in caffeine than black tea.
How to Brew Black Tea for More or Less Caffeine
- Steep time: longer steeping changed the caffeine in lab tests (Chin et al., 2008); a shorter steep gives a lighter cup.
- Cup size: a 16 oz mug holds about twice the caffeine of an 8 oz cup (USDA FoodData Central).
- One bag or two: doubling the tea in the same water makes a stronger cup.
- Decaf: decaffeinated teas had under 12 mg per serving in lab tests (Chin et al., 2008).
- Herbal: herbal teas had no caffeine detected (Chin et al., 2008), which makes them an easy evening choice.
Black tea is a common base for kombucha, which ends up with less caffeine per glass than the tea itself; see does kombucha have caffeine.
What Else Is in Black Tea?
Black tea gets its color and much of its taste from theaflavins and thearubigins, compounds formed when the leaf's catechins are oxidized during processing; most of these compounds readily bind with caffeine (Graham, 1992). Tea also naturally contains L-theanine, an amino acid. In a placebo-controlled study, 50 mg of caffeine with 100 mg of L-theanine improved speed and accuracy on an attention switching task (Owen et al., 2008), one reason many people find tea a calmer lift than coffee. Read more in L-theanine and caffeine.
How Many Cups of Black Tea a Day?
The FDA cites 400 mg of caffeine a day as an amount not generally linked to negative effects for most adults (FDA). At about 47 mg per 8 oz cup (USDA FoodData Central), that is a lot of tea, but black tea adds to coffee, soda and chocolate in your daily total. If tea late in the day affects your sleep, see how long caffeine lasts, and for limits see how much caffeine is too much. Our guide to caffeine in decaf coffee covers decaf tea and coffee.
Where Our Products Fit
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Frequently Asked Questions
How much caffeine is in a cup of black tea?
About 47 mg in an 8 oz cup of brewed black tea (USDA FoodData Central), and about 71 mg in 12 oz (FDA).
Does black tea have more caffeine than coffee?
No. Brewed coffee has about 95 mg per 8 oz, about twice black tea (USDA FoodData Central; USDA FoodData Central).
Does black tea have more caffeine than green tea?
On average, yes: about 47 mg against about 28 mg per 8 oz (USDA FoodData Central; USDA FoodData Central), though individual teas overlap (Chin et al., 2008).
How much caffeine is in a black tea bag?
Brewed teas ranged from 14 to 61 mg per 6 or 8 oz serving in lab tests, depending on the product and steep time (Chin et al., 2008).
Does steeping black tea longer add caffeine?
It can. Steep time affected caffeine concentration in lab tests of brewed teas (Chin et al., 2008).
Is black tea OK to drink at night?
It has caffeine, about 47 mg per 8 oz (USDA FoodData Central), so decaf or herbal tea is the safer evening choice if you are sensitive.
How much caffeine is in decaf black tea?
Decaffeinated teas had less than 12 mg per serving in lab tests (Chin et al., 2008).
Is Earl Grey or English breakfast tea higher in caffeine?
Both are black teas, so expect a similar range of about 47 mg per 8 oz on average (USDA FoodData Central); the brand and how long you steep matter more.
How much caffeine is in 12 oz of black tea?
About 71 mg, the FDA’s typical figure for 12 fluid ounces of black tea (FDA). The USDA value of 20 mg per 100 g gives the same answer, since 12 fl oz of brewed tea weighs about 355 g (USDA FoodData Central). That is less than the 113 to 247 mg the FDA lists for 12 oz of regular brewed coffee.
How much caffeine is in a 16 oz black tea?
About 95 mg, calculated from the USDA value of 20 mg per 100 g for a 16 fl oz (474 g) serving (USDA FoodData Central). That is about the same as an 8 oz cup of brewed coffee, which USDA lists at about 95 mg (USDA FoodData Central). Steep time changes the real number (Chin et al., 2008).
How much caffeine is in black tea per 100 ml?
About 20 mg. USDA lists 20 mg of caffeine per 100 g of brewed black tea, and brewed tea weighs close to 1 g per ml: 8 fl oz, or 237 ml, weighs 237 g (USDA FoodData Central). So a 250 ml mug holds about 50 mg and a 350 ml mug about 70 mg.
How many cups of black tea add up to 400 mg of caffeine?
Eight 8 oz cups at about 47 mg each come to roughly 376 mg, close to the 400 mg a day the FDA cites as an amount not generally linked to negative effects for most adults (FDA). Coffee, soda and chocolate count toward the same daily total. If you are pregnant, trying to become pregnant or breastfeeding, the FDA advises asking your health care provider whether you should limit caffeine.
Sources
- U.S. Department of Agriculture. FoodData Central: Beverages, tea, black, brewed, prepared with tap water (FDC 173227); Beverages, tea, green, brewed, regular (FDC 171917); Beverages, coffee, brewed, prepared with tap water (FDC 171890). FoodData Central
- U.S. Food and Drug Administration. Spilling the Beans: How Much Caffeine Is Too Much? FDA
- Chin JM, Merves ML, Goldberger BA, Sampson-Cone A, Cone EJ. Caffeine content of brewed teas. J Anal Toxicol. 2008. PubMed 19007524
- Graham HN. Green tea composition, consumption, and polyphenol chemistry. Prev Med. 1992. PubMed 1614995
- Owen GN, Parnell H, De Bruin EA, Rycroft JA. The combined effects of L-theanine and caffeine on cognitive performance and mood. Nutr Neurosci. 2008. PubMed 18681988
Our products are not intended to diagnose, treat, cure or prevent any disease. This article is for education only and is not medical advice.
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